Drive device

Abstract

A planetary gear mechanism includes a sun gear, planetary gears, an annular internal gear, a carrier that is fixed to a bracket and includes a second lid, and a support shaft. An output unit is supported to be rotatable by a first bearing attached to the support shaft and a second bearing attached to the bracket, and fixed to the internal gear. The bracket includes a protrusion protruding from a first lid to one side in the axial direction. A radially inside surface of the protrusion includes a first curved surface extending in a circumferential direction as viewed along the axial direction. The carrier includes a second curved surface located radially inside the first curved surface. The second curved surface extends in the circumferential direction as viewed along the axial direction, and contacts with the first curved surface.

What is claimed is: 
     
       1. A drive device that rotates a wheel, the drive device comprising:
 a motor including a motor shaft disposed along a center axis; 
 a planetary gear mechanism connected to one side in an axial direction of the motor shaft; and 
 an output unit to which rotation of the motor shaft is transmitted through the planetary gear mechanism; wherein the motor includes:
 a rotor including the motor shaft; 
 a stator opposed to the rotor in a radial direction with a gap interposed therebetween; and 
 a bracket including a first lid covering one side in the axial direction of the stator; 
 
 the planetary gear mechanism includes:
 a sun gear provided at a portion on one side in the axial direction of the motor shaft; 
 a plurality of planetary gears that are arranged along a circumferential direction on one side in the axial direction of the first lid to engage with the sun gear; 
 an annular internal gear that surrounds a radial outer periphery of the plurality of planetary gears to engage with the planetary gears; 
 a carrier including a second lid located on one side in the axial direction of the planetary gear, the carrier being fixed to the bracket; and 
 a support shaft that is attached to the carrier to extend from the carrier to one side in the axial direction along the center axis; 
 
 the output unit is supported to be rotatable about the center axis by a first bearing attached to the support shaft and a second bearing attached to the bracket, and fixed to the internal gear; 
 the bracket includes a protrusion protruding from the first lid to one side in the axial direction; 
 a radially inside surface of the protrusion includes a first curved surface that extends in the circumferential direction as viewed along the axial direction; 
 the carrier includes a second curved surface located on a radial inside of the first curved surface; and 
 the second curved surface extends in the circumferential direction as viewed along the axial direction, and contacts with the first curved surface. 
 
     
     
       2. The drive device according to  claim 1 , wherein the second bearing is attached to the protrusion. 
     
     
       3. The drive device according to  claim 1 , wherein the protrusion has a cylindrical shape; and
 the first curved surface has a circular shape as viewed along the axial direction. 
 
     
     
       4. The drive device according to  claim 3 , wherein
 the carrier includes a plurality of legs extending from the second lid to another side in the axial direction; 
 the plurality of legs are fixed to the bracket and disposed along the circumferential direction on a radial inside of the protrusion; and 
 each of radially outside surfaces of the plurality of legs includes the second curved surface. 
 
     
     
       5. The drive device according to  claim 1 , wherein
 the first lid includes a first hole recessed on the other side in the axial direction; 
 the second lid includes a second hole recessed on one side in the axial direction; 
 the first hole and the second hole overlap each other as seen along the axial direction; 
 the planetary gear mechanism includes a planetary gear shaft that penetrates the planetary gear in the axial direction to rotatably support the planetary gear; 
 an end on one side in the axial direction of the planetary gear shaft is fitted in the second hole; 
 an end on the other side in the axial direction of the planetary gear shaft is fitted in the first hole; and 
 the bracket includes a positioning unit that is opposed to one side in the circumferential direction of the carrier while contacting with one side in the circumferential direction of the carrier. 
 
     
     
       6. The drive device according to  claim 5 , wherein
 the carrier includes a leg extending from the second lid to the other side in the axial direction; 
 the leg is fixed to the bracket; 
 the radially outside surface of the leg includes the second curved surface; and 
 the positioning unit is located radially inside of the protrusion, and opposed to one side in the circumferential direction of the leg while contacting with one side in the circumferential direction of the leg. 
 
     
     
       7. The drive device according to  claim 1 , wherein
 the planetary gear is located radially inside of the protrusion; and 
 the planetary gear and the protrusion are opposed to each other in the radial direction with a gap interposed therebetween. 
 
     
     
       8. The drive device according to  claim 1 , wherein the planetary gear, the protrusion, and the second bearing include portions located at an identical position in the axial direction. 
     
     
       9. The drive device according to  claim 1 , wherein
 the bracket includes a holder that holds a motor bearing rotatably supporting the motor shaft on the other side in the axial direction of the planetary gear; and 
 the motor bearing overlaps with the planetary gear as viewed along the axial direction. 
 
     
     
       10. The drive device according to  claim 1 , wherein the first curved surface and the second curved surface are cutting surfaces.